Mechanical pencil

ABSTRACT

A mechanical pencil having an axial pushbutton for depressing light and heavy series-mounted compression springs to move the writing lead to any one of three pre-selectable cam-set positions: (a) retracted, (b) extended for writing, and (c) further extended to feed more lead; successive depressions of the light spring extend and retract the lead; depressing the light spring and continuing through with further pressure depressing the heavy spring (longer stroke) moves the mechanism to the lead feed position; the lead is always returned to the extended or writing position after lead feed by action of coaxial cylindrical sleeve camway and cam follower arrangements comprising two-island and series related single-island camway patterns in various embodiments.

United States Patent 1 1 I 1111 3,814,524

Sperti 1 June 4, 1974 1 MECHANICAL PENCIL Primary liruminerLawrence C harlcs [76] Inventor. Vincent R Spem 3718 Valley Hi" Armrney, Agent, or Firm.1ohn F. McClellan, Sr.

Dr., Randallstown, Md. 21133 [22 Filed: May 15, 1973 1 71 ABSTRACT [211 App]. NO: 360,444 A mechanical pencil having an axial pushbutton for depressing light and heavy series-mounted compression springs to move the writing lead to any one of [521 US. Cl 401/57, 401/62, 401/67, three pr.gelctable met positions: (a) retracted,

401/1 (h) extended for writing, and (c) further extended to [51] Int. Cl 843k 27/20, 843k 24/08 f d more lead; successive depressions of the light 01 Search 1 1, pring extend and retract the l ad; d pr i g th 401/62, 55/ 67 spring and continuing through with further pressure depressing the heavy spring (longer stroke) moves the 1 1 References Cited mechanism to the lead feed position; the lead is always UNITED STATES PATENTS returned to the extended or writing position after lead 387,042 7/1888 Bohren 401/62 feed by action of waxifll Cylindrical Sleeve Cflmway 420.033 1/1890 Bohren 401/20 n m f ll r rrang m nt mpri ing -i l n and series related single-island camway patterns in FOREIGN PATENTS OR APPLICATIONS various embodiments.

1,911,585 10/1970 Germany 401/ 41 Claims, 41 Drawing Figures POSITION minimum 4 I974 $814524 sum 5 0F 8 MECHANICAL PENCIL This invention relates generally to mechanical pencils and specifically to push button operated pencils having provision for extended-length adjustment as well as for extension retraction for writing and storage.

In prior art mechanical pencils of the type described, two principal faults have limited widespread commercial and user acceptance. First, the mechanisms have been complex and relatively expensive. Second, the operation has been awkward and inconvenient. In particular, presently available mechanical pencils of the type described require, in use, passing through the adjustment stage to reach the extended-for-writing stage.

Principal objects therefore of the present invention are to provide a pushbutton operated mechanical pencil mechanism which is extremely convenient and natural to use, which is adpatable to various embodiments, and which is at the same time reliable and economical.

More specific objects through which the above objects are realized are to provide a pencil which extends to the writing position andretracts from the writing position without passing through the lead feed position; which returns to the writing position after being placed in the lead feed position, which requires minimum effort to extend and retract. which in an embodiment will release the lead for free extension and which in another embodiment will positively feed the lead always in the same pre-determined increment regardless of the length of push button stroke.

In a simplified statement of an embodiment the invention includes three co-axial, relatively sliding members, the outer and middle members being related by a light spring, the the middle and inner members being related by a heavy spring and sleeve and collet terminal structure, and the outer and inner elements being related by a cam follower and camway arrangement and plunger terminal structure.

The above and other advantages and objects of the present invention will become more readily understood on examination of the following description including the drawings, in which:

FIG. I is a side view;

FIG. 2 is a side detail in partial section;

FIG. 3 is a side view;

FIGS. 4-7 are side details in partial section;

FIGS. 8-26 are details in developed side view;

FIG. 27 is an isometric detail;

' FIG. 28 is an exploded side-view of a subassembly partially in section;

FIG. 29 is an isometric view;

FIG. 30 is a side section;

FIGS. 31-33 are isometric views;

FIGS. 34-36 are side details in partial section;

FIG. 37 is a cross-section;

FIG. 38 is a side view in partial section;

FIG. 39 is a detail in side view; and

FIGS. 40-41 are cross-sections.

In the following description'the figures are described in sequence and like numerals indicate like parts.

FIGS. 1-7 show assembly details of a first embodiment 10 of the invention. A broader statement of the relations of the major assemblies will be given in reference to FIGS. 4-7.

EXTERIOR STRUCTURE OF FIRST EMBODIMENT FIG. 1 shows exterior features of the embodiment 10 including a plunger cap or plunger 12 reciprocable in an upper ferrule or upper body 14 which in turn attaches at a screwjoint 16 to a lower ferrule or body 18 terminating in a tip 20 from which a lead support 22 supporting lead 24 is extensible. The upper body in.- cludes an upper body cap 26, preferably having an integral clip 28 of conventional design spanning a substantial reduced diameter length 30 of the upper body and tapering to and terminally bearing on a full diameter length 32 of the upper body which is the same diameter as lower body uniform diameter portion 34 above the portion 36 tapering to the tip. The clip/body diameter relation provides room for bulky'material under the clip while at the same time keeping the pencil center of gravity low and providing a satisfying handgrip.

GENERAL INTERIOR STRUCTURE OF FIRST EMBODIMENT 46, the upper bore oflarger diameter, meeting at an upwardly facing interior shoulder 48. Press-fit with the lower body retains the tip.

In exterior shape, lead support 22 has two co-axial portions 50 and 52 of different diameters, the upper being larger and a shoulder 54 complementary to the corresponding features of the tip within which the lead holder is slidable under the thrust of an incremental adjustment sleeve 56. The lead support is attached to the incremental adjustment sleeve by screw threads 58. The incremental adjustment sleeve is reciprocable by action of plunger 12 (FIG. 1) acting on intermediate structure not shown, and in turn strong spring 60 and upper flange 62, and has a flange-engaging return spring or weak spring 64 which seats against the upper end of the tip structure, as will be further apparent in relation to later figures.

The lower end of the lead support is split as will be seen in succeeding figures and sprung inward to tighten support of the lead 24 and retain short pieces. A friction sleeve 66 of rubber or other suitable material, set into the bore of the lead support at interior shoulder 68, applies a degree of restraint to axial movement of the lead through the lead support.

Incremental adjustment sleeve 56 has a bore constriction 70 forming upper and lower interior shoulders 72 and 74 at the ends of the construction.

Collet locking sleeve 76 which has a downwardly bell-mouthed bore is free to slide axially inside the incremental adjustment sleeve between bore construction lower shoulder 74 and the upper end 78 of lead support 22, which serves to stop the downward travel of the collet locking sleeve and disengage it from the collet head 80 allowing the collet head to spring open and release the lead on continued downward travel of the collet head. Collet head 80, which is split as at 82, has toothed lead gripping jaws 84, and acollet-lockingsleeve-engaging-shoulder 86, is free to slide within the axial space between the top of friction pad 66 and the full-engagement position with collet locking sleeve 76 when the collet locking sleeve engages shoulder'86. Collethead 80 is attached-at the upper end to plunger tube 88 as by screwthreads 90, and the plunger tube slidably fits the bore of incremental adjustment sleeve 56. I

FIG. 3 is an exterior view of the operating parts of the pencil assembly removed as a unit from the encil body. Plunger tube 88 by means of friction overlap limited by upper shoulder 92 supports plunger 12 at the top and passes downward through a cylinder-shaped cam track sleeve or camway sleeve 94, a thrust washer 96 which bears on tapered shoulder 97 near the lower end of the camway sleeve, strong spring 60, and incremental adjustment sleeve 56 which, in turn, passes through weak spring64. Lead support 22 longitudinally split at 98, joins, as noted, the bottom end of incremental adjustment sleeve, and lead 24 protrudes from the lead support. The two springs 60 and 64 oppose at flange 62 of the incremental adjustment sleeve. Annular flange 100, integral with plunger tube 88 is-spaced from lower shoulder 97 allowing free rotation of camway sleeve 94 which has a cam track or camway pattern 102 formed in the cylindrical surface. The lower end of the camway sleeve terminates in an integral annular flange 104 of larger diameter.

Camway sleeve 94 passes through, or in part is surrounded by, cam follower sleeve 106, which bears a fixed, inwardly protruding cam follower 108. The cam follower sleeve may have differing-diameter upper 110 and lower 112 portions as shown, to fit within adjacent structures.

FIGS. 4 through 7 show in partial section the relations of the parts of embodiment of the invention and successive stages of operation. All these figures show the same structure broken away in different manners for-purposes of exposition. FIG. 4 indicates additionally the structure of the plunger 12 fitting axial aperture 114 in the upper body 14. y

In reference to FIGS. 4.7 it should be noted that cam follower sleeve 106 which is integral with cam follower 108 is preferably tightly constrained but may be loosely and rotatably constrained in a space 116 between the top 118 of the lower body and aninterior flange. 120

provided for the purpose in the upper body; Axial extent of the space 116 is fixed by the abutting relation of the upper and lower body at screwjoint 16.

The camway pattern 102 in camway sleeve 94 is generally lenticular in outline and has first and second cam elements, in this embodiment both are islands.

The first cam element comprisesa first, lower and larger assymmetrical shield-shaped island 124 having a concave upper surface 126, and a second, upper and a smaller polygonal, generally lenticular shaped island 122 tipped in diagonal disposition with respect to the camway long axis above the lower cam element. The tip of the upperisland and the assymmetry of the lower island may be in either direction, left or right, but the smaller side 128 of the-lower island (as opposed to the fuller side 130) which descends past the cam follower in operation begun from the retracted position; is on the side toward which the upper island is tipped. The fuller side 130 of the lower island protrudes laterally beyond the lateral extent of the upper island and above this protrusion the periphery of the camway forms an inwardly turning section 132 in the channel 134 passing generally upright past one side of the islands so that when the camway ascends when the cam follower is adjacent the upper island in the upper reaches of channel 134, the cam follower will be captured in the transversely connective upwardly concave channel 126 at the top of the lower island, establishing the writing position. The opposite or ascending generally upright channel swings out around the opposite side of the islands in a relatively smooth curve. A filler slot or assembly slot 138, open at the end, may be provided communicating-with the cam way for insertion of the cam follower. I

, RELATION OF-TI'IE PARTS AS MAJOR SUB-ASSEMBLIES For operational description purposes the mechanism of the embodiment-10 groups into three interacting units, as follows: 7

I. Outer unit, comprising the body l4, 18, of the pencil and the cam follower sleeve 106 retained by. the

body;

II. Intermediate unit, comprising the incremental adjustment sleeve 56 and the attached lead support III. Inner unit, comprising the plunger 12, plunger tube 88, camway sleeve 94, collet head 80, and collet locking sleeve 86.

' The outer unit (body, cam follower sleeve) is related to the intermediate sleeve(lead support) by weak compression-spring 64 which bears on the upper end of the tip 20 and on the lower face of incremental adjustment sleeve flange 62.

The intermediate unit is related to the inner unit (plunger, plunger tube, camway sleeve, collet head and locking sleeve) by the strong compression spring 60 which has a spring rate considerably greater than the weak compression spring, the ends of which strong spring respectively bear against the upper face of flange 62 and the lower face of thrust washer 96 and by the heavy-spring-produced contact between the upper end of collet locking sleeve 76 and internal shoulder 74- of the constriction in the incremental adjustment sleeve.

The inner unit is related to the outer unit by the coaxial serial extent of springs'60 and 64 between the upper end of tip 20 and the lower face of incremental adjustment sleeve flange 62, and by engagement of cam follower 108 with camway pattern 102.

Relation of the parts and precompression of the springs on assembly of the parts sets up the following forces which obtain at all positions except the lead-feed position of FIG. 7; the serial springs 60 and 64, urge camway'sleeve 94 upward against the restraint of the cam follower 108, and strong spring 60 compresses weak spring 64 to a degree tensioning plunger tube 88 between internal shoulder 74 of incremental adjustment tube constriction 70 and'plunger tube tapered shoulder 97. 4

OPERATION, WRITING POSITION TO STORAGE POSITION AND RETURN a. Proceeding from the WRITING POSITION of FIG. 4, to the STORAGE POSITION of FIG. 5, depression of plunger 12 to the limit of travel when lead support shoulder 54 reaches tip interior shoulder 48 limiting the travel of weak spring 64 and developing the resistance of strong spring 60, which transition can be clearly sensed by the user, moves camway sleeve 94 downward, causing the tipped, diamond shaped upper island 122 to descend against cam follower 108, rotating the camway sleeve to the right (counterclockwise as viewed from the top of the pencil) freeing the cam follower from the concave upper face 126 of shieldshaped lower island 124 at the writing position a and aligning the ascending side channel 136, the left hand. with the cam follower at about position b, the STOR- AGE TRANSIENT POSITION of FIG. 6; relaxation of pressure on the plunger then causes the camway sleeve to pass upward under weak spring return until stopped by contact of the V-shaped bottom notch 140 of the camway with the cam follower as in FIG. 5, in position c, the STORAGE POSITION.

b. Proceeding from the STORAGE POSITION of FIG. 5 to the WRITING POSITION of FIG. 4, depression of plunger to the limit of travel of weak spring 64 moves the camway sleeve downward. causing the fuller lower face 130 of assymetrical shield shaped lower island 124 to deflect against the cam follower, rotating the camway sleeve to the left, moving descending channel 134 (the right hand channellpast the cam follower until peripheral inward-turned section 134 of the camway strikes the cam follower, rotating the camway to the right, aligning the upper right channel with the cam follower at about position d; relaxation of pressure on the plunger then causes the camway sleeve to rise, seating the cam follower in the assymetrical concave face 126 of the top of the lower island as in FIG. 1 in position a, the WRITING POSITION.

OPERATION, FEEDING EXTRA LEAD a. Beginning with the WRITING POSITION of FIG. 4, in feeding extra increments of lead to increase protrusion of the lead from the end of lead support 22, the plunger 12 is depressed past the travel limit of weak spring 64 and well into the compression range of strong spring 60, the cam follower and camway passing through relative position d the LEAD FEED TRAN- SIENT POSITION of FIG. 7, advancing and freeing the lead by contact between the lower end of collet locking sleeve 76 and the upper end 78 of lead support 22, which allows the collet head 80 to spring open. When pressure on the plunger is released, the frictional insert 66 holds the lead while the collet returns and regrips on contact between the upper edge of the collet locking sleeve 76 and constriction shoulder 74. This incremental lead-feeding may be repeated as many times as desired by reciprocating the plunger against the pressure of the strong spring to cause camway sleeve movement relative to the cam follower between positions a and e, obtaining an incremental advance each troke; return to the WRITING POSITION, a of FIG. 1 is automatic when plunger pressure is released. Return to the storage position, is as previously described, obtained by relatively short stroke of the plunger against resistance of the weak spring only.

b. Beginning from the STORAGE POSITION, c FIG. 5, lead feed is obtained in the same manner as described above. by full stroke of the plunger passing from c to e, through the weak spring range into the strong spring range; as before, return is automatic to the WRITING position on removal of the plunger pressure.

DETAILS OF OPTIONAL CAMWAYS The next nineteen figures show alternative patterns of camways in developed detail, all usable with embodiment l0. Successive relative positions of cam follower and camway are indicated by arrow tracks and letters and circled numbers.

From the foregoing descriptions of relative cam and camway travel it will be seen that the following general positional descriptions define the lettered positions of cam relative to camway;

a writing position: from a can rise and drop to h or can rise and go over island to e and d and then to a again;

b the point of decision from a, can either drop to c or rise to go over the island;

0 storage;

d point of decision as to whether, from storage, to drop back to a or to pump lead at d-e and then drop back to a;

e topmost point attainable from storage.

Additionally with regard to the following, optional camways, the following letters, where they appear, define the following positions:

' e similar to e but topmost point attainable from a writing position;

f position reached from storage at which must drop back to a, writing position.

FIG. 8 shows a camway pattern 8102 similar to previously described camway pattern 102 of FIGS. 4-7 except that no filler slot is provided: the resultant closed pattern is otherwise a mirror image of pattern 102; there is nothing to choose between lefthand and righthand patterns. Various means of engaging the cam follower with the camway without necessity for a filler slot will be disclosed in reference to later figures.

FIG. 9 shows a circumferential series of camway patterns 9102 in a camway sleeve 994. All have bellmouthed filler slots 9138, 9142, at top and bottom but are otherwise like the FIG. 8 pattern. The FIG. 9 pattern and other multiple patterns disclosed in following figures are all adapted for use with multiple cam followers, one to a pattern being the maximum practical numher, or any mutliple pattern can be used with as few as one cam follower. The FIG. 9 pattern is nonprogressive in that a pattern works with the same cam follower at all times rather than having the capability to progress to another cam follower. The bellmouthed design of filler slots 9138, 9142, freely allows travel of the cam follower beyond the cam track but always indexes properly on return.

FIG. 10 illustrates a progressive pattern of serial closed (not filler slot) camways 10102 basically similar to the FIG. 8 camway pattern but with the shield shaped lower island 8124 of FIG. 8 converted in each case to a penisular 10124 having the same type top shape as before but with the bottoms solid and straight channels 10134 bounding the sides.

FIG. 11 shows a series of patterns 11102 similar to that of FIG. 10 with bellmouthed filter slots 11138, 11142, at the top and bottom.

FIG. 12 discloses that each of a series of patterns 12102 similar to those of FIG. 10 can have an offset bellmouthed filler slot 12142 connecting with the offset hooked sides of lower ends of the channels.- This inventive feature allows free and properly indexing first insertion of a cam follower or followers in the camway, and thereafter limits the stroke in the manner of a closed camway by thereafter hooking and capturing the cam follower in hook 12143.

FIG. 13 shows a series pattern 13102 like that of FIG. but with a bellmouthed filler channel 13138 at the top of each pattern.

FIG. 14 discloses a single camway pattern 14102 like that of FIG. 8 except for two features. The first feature is that the peripheral inward-turned section of the descending channel forms a hook 14144 which forces the cam follower and camway into the writing position at a before itis possible to advance to the lead feed position between b and e, thus avoiding the need to have enough differential between the spring rates of the light and heavy springs to signal the point in the stroke at the end of the light spring travel which marks the beginning of the lead-feed stroke. The second feature is a lower filler slot 14142 offset to the side of the descending channel near the bottom.

FIG. 15 shows a non-progressive series 15.102 of the FIG. 14 patterns having an interconnection throughthe bellmouthed filler slots 15142 which have an'offset gut 15145 which provides the same features recited in reference to FIG. 12.

FIG. 16 shows a pattern series 1694 like that of FIG. 15 but with bellmouth top filler slots 16138 and with bellmouthed bottom filter slots 16142 directly under each lower island 16124.

FIG. 17 shows a serial pattern 1794 like that of FIG.

16 but made progressive by provision of common channels 17134 below the level of the tops 17126 of the lower islands 17124, which .islands are positioned closely enough together to define the channels by the boundaries of the islands.

FIG. 18 shows a progressive serial camway pattern like that of FIG. 7 but with the lower islands bounded by straight channels 18134 joined at the bottoms, forming peninsulas 18124.

FIG. 19 shows a long-wear single closed pattern 19102 like that of FIG. 14, but without a filler slot and with a dead-end vertical channel 19146 communicating with the upper portion of the hook-shape 19144 of the peripheral inward turned section, allowing lead feed within the length of the vertical channel directly from the storage position, or alternatively from the rest 8 under assembly force but retentive of the cam follower once captured.

FIG. 25 shows the FIG. 24 pattern with ellmouthed fillers 25138 and 25142, top and bottom. the bottom position as previously described in reference to the first embodiment.

FIG. 20 illustrates bellmouthed filler slots..20138, 201.42, 20148 connecting directly to all the respective channels in a nonprogressive camway serial pattern 20102 otherwise like that of FIG. 19.

FIG. 21 shows the FIG. 20 pattern generally but made progressive with the lower islands'converted to parallelsided adjacent peninsulas 21124 connected at the bottoms by solid structure. I

FIG. 22 shows a serial pattern 22102 like that of FIG. 21 but with bellmouthed filler slots 22138, 22148 and 22142 at all channels, top and bottom.

FIG. 23 shows a serial pattern 23102 like the FIG. 22 pattern with the tops of the vertical channels 23146 above the hook portions closed.

FIG. 24 depicts a progressive serial pattern 24102 I similar to that of FIG. 10 but with the peninsulas 24124 laterally offset one-half cycleof the pattern with re spect to the upper islands 24122, with each upper island having a recess 24150 in the lower portion preventing going directlyfrom the storage position to the lead feed position. Additionally,-a filler slot or slots 24142 may be provided as shown with a constriction or constrictions 24141 passable by the cam follower fillers 25142 joining below to convert the peninsulas to islands 25124.

FIG. 26 shows a serial pattern 26102 similar to that of FIG. 24 with the peninsulas converted to lower shield-shaped islands 26124 by curve and junction of adjacent pairs of channels 26134 and 26136. The upper islands 26122 are isosceles triangles with one edge vertical, the apices pointing in the direction of progression. This arrangement permits the cam follower to have relative movement from c directly to e.

FIG. 27, an isometric view of an upper body 2714, shows that the cams need not be part of a separate cam follower sleeve as previously described, but instead can be an integral part of the pencil body, theupper part 2714 of which can terminate in one or more axially aligned prongsv 17152 or equivalent structure having a cam follower or cam followers 27108 protruding inwardly to engage the camway.

FIG. 28'ill ustrates one relation of the parts accomplished in the above, in which upper body 2714 receives plunger 2712, which may have an internal spring, not shown, to keep it protruding at all times, arranged for resting on the top 28154 of the camway cup 2894 show closed to provide inner and outer thrust surfaces for the spring and the top of the plunger tube previously described. This arrangement uses the spring of the prongs for assembly in the absence of filler slots in the camway; the integral cam structure is economical to produce, and the increase in friction over the loosely held separate cam follower structure previously described is not excessive.

FIG. 29 illustrates a filler-slot eliminative cam sleeve 29106 having cam followers 29108 resiliently mounted on tabs 29156 separated by a peripheral slot 29158 on three sides from the sleeve. I

'FIG. 30 shows a cam follower sleeve 30106 having threads 30160 top and bottom, spaced by an outer annulus 30162, for joining theupper body and lower body, and having a fixed inward 'cam'follower 30108 and a slidable cam follower in the form of a cylinder 30108 held in a cylindrical radial aperture through the annulus.

The slidable cam follower is held in place by friction, on assembly, and eliminates the need for filler slots in the camway or for elasticmernbers to hold the cam follower.

FIG. 31 illustrates a simple elastic snapring cam follower holder 3ll06.'of wire or the like having inwardly turned ends which serve as cam followers 31108; this is held by being gripped-tightly between the upper and lower bodies of the pencil.

FIG. 32 illustrates a filler-slot eliminative semicylindrical snapring type sleeve 32106 with inwardly protruding cam followers 32108.

FIG. 33 shows a cam follower sleeve 33106 similar to that of FIG. 32 but with a circumferential slot 33164 adapted to position one or more spheres 33108 which act as cam followers. This is a low-friction arrangement, relatively economicaLand capable of instant adaptation to engagemultiple serial camway patterns, by addition of spheres. I

MODIFIED FEED STRUCTURE EMBODIMENT FIGS. 34, 35 and 36 show three positions, writing, storage, and lead-feed respectively. of an embodiment 3410, similar to that of FIGS. 16. However, in contrast, no lead support is provided beyond collet 3480, no friction holding resilient member is provided, no separate collet locking sleeve and lost-motion incremental-feed shoulders are provided, but instead the collet 3480 is sleeved directly in the lower end of sleeve member 3456 which served as an incremental advance sleeve in the prior embodiment; and additionally, a shoulder 3457 is provided to engage flange 3462 of sleeve member 3456 to limit the stroke compressing weak spring 3464 and initiate compression of strong spring 3460, and the V-shaped notch at the bottom of the camway pattern 34102 is elongated downwardly into channel 34140 to accommodate the extra stroke length employed. When collet 3480 is released by depressing the plunger' (not shown) and plunges tube 3488 into. the compression region of strong spring 3460, the lead 3424 falls freely. Adjustment is made by allowing the lead to drop a predetermined distance to a table surface or the like, and then releasing the plunger, locking the lead in that position. This embodiment is extremely rugged and economical, and allows the use of large, strong leads without undue bulk in the pencil.

CROSS-SECTION OF FIRST DESCRIBED EMBODIMENT FIG. 37 is a section taken at 37-37, FIG. 4, showing the co-axial relation of leads 24 stored, plunger tube 88, camway sleeve 94, cam follower sleeve 106 and cam follower 108, and upper body 14.

INVERTED-CAM EMBODIMENTS The remaining figures illustrate embodiments of the invention in which the camways are internal to the cylindrical'surfaces or sleeve structure defining them, and in which the cam followers protrude radially outwardly rather than inwardly, the net result being a similar function, with generally more room for the camways, and shorter coupled cam followers; the other arrangements in the pencil being as before described.

FIG. 38 shows in section an upper body 3814 having a typical camway pattern 38102 inscribed or cast in the inner periphery, the material preferably being a common thermoplastic such as polystyrene, which can be used in construction of any of the camway sleeves, cam followers, or pencil bodies described. The cam follower arrangement may be generally as in the remaining figures.

FIG. 39 shows an inverted cam follower and sleeve arrangement, for use with the embodiment of FIG. 38, in the form of a cylindrical snap-ring 39016 bearing outwardly oriented cam followers 39108 and fitted be tween specifically provided upper and lower flanges 39166 and 39168 on the outer surface of a plunger tube 3988 adapted for the purpose.

FIG. 40 shows a cross-section through the upper body of an alternative embodiment of the pencil of this invention similar in inverted arrangement to that disclosed in the previous two figures, but with an assembly facilitating, filler slot eliminating feature: the camway sleeve is separate from the pen and is in two parts 40102, 40102, separated by longitudinal seams 40170.

The cam follower sleeve 40106 may be friction fitted to the plunger tube 88 and solid as shown.

FIG. 41 shows a similar cross-section of a further inverted cam embodiment in which the camway sleeve 41102 has a key 41172 locking it to the cam follower sleeve 41106 which in turn has a slot 41164 which retains a sphere 41108.

Each of the embodiments described has a particular economy in compactness, simplicity of assembly, and ruggedness, although differeing from the others, and it is to be understood that the types disclosed are compatible, in the light of the herein description.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed and desired to be secured by United States letters patent is:

l. A writing instrument having lead or the like therein, comprising: means for releasibly holding lead, means for housing the lead holding means, means for moving the lead holding means axially downward in the housing means, means for signalling division of the axial movement into a first stroke region and a second stroke region sequentially following the first stroke region, means for positioning the lead holding means for storage at the beginning of the first stroke region, the lead holding means for writing at the end of the first stroke region, and the lead holding means for feeding lead adjacent the end of the second stroke region; means for feeding lead through the lead holding means in the second stroke region, and means for requiring return of the lead holding means to said writing position after feeding lead through the lead holding means.

2. A writing instrument as recited in claim 1, wherein the lead holding means comprises a collet, and wherein the means for feeding lead comprises a locking sleeve releasibly affixed to the collet for movement therewith through said first stroke-region, and a shoulder fixed in the'downward path of movement of the locking sleeve in position for preventing the locking sleeve from moving downward with the collet in said second stroke region, thereby releasing the collet and the lead for feeding through the collet.

3. A writing instrument as recited in claim 2, wherein the locking sleeve has a flange thereon, wherein said shoulder fixed in the downward path of movement of the locking sleeve is fixed to the housing means, wherein the housing meanshas a second shoulder below the first said shoulder, wherein a first resilient compression means extends between the second said shoulder and the flange, and a second resilient compression means extends between the flange and the and wherein downward a t. eiatir rr s q sanimsyin wherein the housing means has an interior shoulder below the flange, wherein a first and relatively weak resilient compression means extends between the housing means interior shoulder and the flange, wherein a second and relatively strong resilient compression means extends between the flange and the means for positioning, wherein means is provided for connecting the means for moving and the-means for positioning for thereby compressing all said resilient compression means on downward movement of the means for movement and whereby compression of the relatively weak resilient compression means to a predetermined length comprises the means for signalling division of the axial movement. 1 I

5. A writing instrument as recited in claim 4, wherein a lead support is affixed to the lower end of the flanged sleeve in coaxial alignment for passage of the lead therethrough, andwherein aresilient member is affixed within the lead support in position to retard movement of passing lead, whereby on incremental advance and release of lead by the collet the lead is fixed in position during retraction and re-engagement of the collet with the locking sleeve. 7

6. A writing instrument as recited in claim 1, wherein the means for moving the lead holding means comprises plunger means, wherein the means for positioning the lead holding means comprises a camway and a cam follower, means on the housing means and means on the plunger means fixing the camway and cam follower in radial, movable relation one to the other with one constrained for movement with the housing means and the other constrained for movement with the plunger means.

7. A writing instrument as recited in claim 6, wherein the camway comprises an assymmetrical lower cam element, an upper generally lenticular-shape cam element diagonally disposed above the lower cam element and perimeter structure defining together with the cam elements: a first channel generally upright one side of the cam elements turning inward over a portion of the side of the lower cam element toward the upper cam element and thereby comprising said means for requir ing return of the lead holding means to said writing position, a second channel generally upright on the opposite side of all said cam elements with the first and second channels joining at the top, a third channel generally upwardly concave channel joining together the first and second channels at a location separating the upper cam element as an island cam.

8. A writing instrument as recited in claim 6, wherein the engagement position of the cam follower with the third channel defines the extended-.for-writing position of the lead holding means, wherein the engagement position of the cam follower with a lower portion of at least one of the generally upright channels comprises the means for positioning the lead holding means for storage, and wherein the engagement of the cam follower with the upper portion of either the first or second channel adjacent the top of the upper cam element comprises the means for positioning the lead holding means for feeding lead.

9. A writing instrument as recited in claim 7, and structure forming a downward facing hook shape in a channel portion above the upper cam element, thereby guiding relative travel of the cam follower from the stqr ss qsitiq q teqluq ihLW iliU 29$. t 9m 10. A writing instrument as recited in claim 9, wherein saidstructure forms the hook shape in the, inward turned portion of the first channel.

11 A writing instrument as recited in claim 9, wherein said structure forms the hook shape in the lower periphery of the upper cam element.

12. A writing instrument as recited in claim 7, whereina plurality of saidcamways is provided in lateral juxtapositionjeach said camway having a channel interconnection on each side with an adjacent said camway.

13. A writing instrument as recitedin claim 12,

wherein said channel interconnection comprises merger of one of said generally upright channels with a next adjacent generally upright channel at the conjuncture of said third channel wherein structure is provided defining a slope of a portion of said third channel adjacent said conjuncture, thereby providing for operative serial transfer of the camways'past the cam follower. A

14. A writing instrument as recited in claim 13, wherein structure is provided defining a filler slot connection with at least one of said channels.

15. A writing instrument as recited in claim 7, wherein structure is provided defining a vertical channel extending from said inward turned portion of the first channel to a position above the upward extent of the upper cam element.

16. A writing instrument as recited in claim 15, wherein in a plurality of said camways is provided, each said camway having a channel interconnection on each side with an adjacent said camway.

17. A writing instrument as recited in claim 7, wherein structure is provided joining the first and second said channels in V configuration below the lower element, and wherein the bottom portion of the lower cam element is laterally offset with respect to the V configuration, thereby providing for the first said channel to descend past the cam follower on operation beginning with the storage position.

18. A writing instrument as recited in claim 17, wherein a plurality of camways is provided in lateral juxtaposition, each said camway having a channel interconnection on each side with an adjacent said camway.

19. A writing instrument as recited in claim 17, wherein structure is provided defining a bellmouth filler slot connection with at least one of said channels.

22. A writing instrument as recited in claim 6,

wherein the cam follower extends radially inwardly and the means on the housing means fixes the cam follower to the housing means, and wherein the camway comprises an exterior cylindrical surface and the means on the plunger means fixes the camway to the plunger means.

23. A writing instrument as recited in claim 6, wherein the camway comprises an interior cylindrical surface and the means on the housing means fix the camway to the housing means, and wherein the cam follower extends radially outwardly and the means on the plunger means fixes the cam follower to the plunger means.

24. A writing instrument as recited in claim 6, wherein the cam follower comprises at least one inward protrusion affixed in the inner surface of the upper part of the housing means.

25. A writing instrument as recited in claim 24, wherein the upper part of the housing means is divided into the shape of a fork, wherein the inward protrusion is affixed to one part of the fork, and wherein a second inward protrusion is provided afiixed to a second part of the fork.

26. A writing instrument as recited in claim 6, wherein the means on the housing means comprises an annular-recess.

27. A writing instrument as recited in claim 26, wherein the means on the plunger means comprises a flange integral with the plunger means.

28. A writing instrument as recited in claim 27, wherein a circular shape holder retained in the annular recess in the housing means secures the cam follower in the inner surface of the circular shape holder and wherein the camway comprises an exterior cylindrical surface movable with the plunger means.

29. A writing instrument as recited in claim 28, wherein the circular shape holder has a resilient arm attached thereto, and wherein the cam follower is affixed to the resilient arm.

30. A writing instrument as recited in claim 27, wherein the circular shape holder comprises a snapring.

31. A writing instrument as recited in claim 27,

V wherein the circular shape holder includes a recess in the inner face receiving the cam follower.

32. A writing instrument as recited in claim 31, wherein recess is annular and wherein the cam follower comprises a sphere movable in said annular recess.

33. A writing instrument as recited in claim 30, wherein the recess is radial and wherein the cam follower comprises an elongate member movable in said radial recess.

34. A writing instrument as recited in claim 26, wherein the housing means is divided transversely at said recess and has internal threads in the divided parts of the recess, wherein a cylindrical member secures the cam follower in the inner face thereof, and wherein the cylindrical member has external threads dimensioned for uniting the threaded divided parts of the housing means.

35. A writing instrument as recited in claim 6, wherein a circular shape holder engages the flange of the plunger means and wherein the cam follower protrudes outwardly from the circular shape holder.

36. A writing instrument as recited in claim 35, wherein the circular shape holder is a snapring.

37. A writing instrument as recited in claim 35, wherein the circular shape holder has a recess therein receiving the cam follower.

38. A writing instrument as recited in claim 37, wherein the recess is annular, and wherein the cam fol lower is a sphere movable in said annular recess.

39. A writing instrument as recited in claim 37,. wherein the recess is radial and wherein the cam follower comprises an elongate member movable in said radial recess.

40. A writing instrument as recited in claim 6, wherein the camway comprises an inward facing integral part of the interior surface of the housing means.

41. A writing instrument as recited in claim 26, wherein the camway comprises an inward facing portion of a cylindrical sleeve divided longitudinally into plural parts and wherein the plural parts are retained in the annular recess in the housing means and means for requiring return of the lead holding means to said writing position after feeding lead through the lead holding means. 

1. A writing instrument having lead or the like therein, comprising: means for releasibly holding lead, means for housing the lead holding means, means for moving the lead holding means axially downward in the housing means, means for signalling division of the axial movement into a first stroke region and a second sTroke region sequentially following the first stroke region, means for positioning the lead holding means for storage at the beginning of the first stroke region, the lead holding means for writing at the end of the first stroke region, and the lead holding means for feeding lead adjacent the end of the second stroke region; means for feeding lead through the lead holding means in the second stroke region, and means for requiring return of the lead holding means to said writing position after feeding lead through the lead holding means.
 2. A writing instrument as recited in claim 1, wherein the lead holding means comprises a collet, and wherein the means for feeding lead comprises a locking sleeve releasibly affixed to the collet for movement therewith through said first stroke-region, and a shoulder fixed in the downward path of movement of the locking sleeve in position for preventing the locking sleeve from moving downward with the collet in said second stroke-region, thereby releasing the collet and the lead for feeding through the collet.
 3. A writing instrument as recited in claim 2, wherein the locking sleeve has a flange thereon, wherein said shoulder fixed in the downward path of movement of the locking sleeve is fixed to the housing means, wherein the housing means has a second shoulder in the path of movement of the flange above the first said shoulder, wherein a first resilient compression means extends between the first said shoulder and the flange, and a second resilient compression means extends between the flange and the means for positioning, and wherein downward movement of the plunger means compresses at least one said resilient compression means moving the flange against the second shoulder, comprises the means for signalling division of the axial movement.
 4. A writing instrument as recited in claim 2, wherein a sleeve having a flange surrounds the collet and locking sleeve, wherein said flanged sleeve bears said shoulder fixed in the downward path of movement of the locking sleeve and bears a second shoulder fixed in the upward path of movement of the locking sleeve wherein the housing means has an interior shoulder below the flange, wherein a first and relatively weak resilient compression means extends between the housing means interior shoulder and the flange, wherein a second and relatively strong resilient compression means extends between the flange and the means for positioning, wherein means is provided for connecting the means for moving and the means for positioning for thereby compressing all said resilient compression means on downward movement of the means for movement and whereby compression of the relatively weak resilient compression means to a predetermined length comprises the means for signalling division of the axial movement.
 5. A writing instrument as recited in claim 4, wherein a lead support is affixed to the lower end of the flanged sleeve in coaxial alignment for passage of the lead therethrough, and wherein a resilient member is affixed within the lead support in position to retard movement of passing lead, whereby on incremental advance and release of lead by the collet the lead is fixed in position during retraction and re-engagement of the collet with the locking sleeve.
 6. A writing instrument as recited in claim 1, wherein the means for moving the lead holding means comprises plunger means, wherein the means for positioning the lead holding means comprises a camway and a cam follower, means on the housing means and means on the plunger means fixing the camway and cam follower in radial, movable relation one to the other with one constrained for movement with the housing means and the other constrained for movement with the plunger means.
 7. A writing instrument as recited in claim 6, wherein the camway comprises an assymmetrical lower cam element, an upper generally lenticular-shape cam element diagonally disposed above the lower cam element and perimeter structure defining together with the cam elements: a firSt channel generally upright one side of the cam elements turning inward over a portion of the side of the lower cam element toward the upper cam element and thereby comprising said means for requiring return of the lead holding means to said writing position, a second channel generally upright on the opposite side of all said cam elements with the first and second channels joining at the top, a third channel generally upwardly concave channel joining together the first and second channels at a location separating the upper cam element as an island cam.
 8. A writing instrument as recited in claim 6, wherein the engagement position of the cam follower with the third channel defines the extended-for-writing position of the lead holding means, wherein the engagement position of the cam follower with a lower portion of at least one of the generally upright channels comprises the means for positioning the lead holding means for storage, and wherein the engagement of the cam follower with the upper portion of either the first or second channel adjacent the top of the upper cam element comprises the means for positioning the lead holding means for feeding lead.
 9. A writing instrument as recited in claim 7, and structure forming a downward facing hook shape in a channel portion above the upper cam element, thereby guiding relative travel of the cam follower from the storage position directly to the lead feed position.
 10. A writing instrument as recited in claim 9, wherein said structure forms the hook shape in the inward turned portion of the first channel.
 11. A writing instrument as recited in claim 9, wherein said structure forms the hook shape in the lower periphery of the upper cam element.
 12. A writing instrument as recited in claim 7, wherein a plurality of said camways is provided in lateral juxtaposition, each said camway having a channel interconnection on each side with an adjacent said camway.
 13. A writing instrument as recited in claim 12, wherein said channel interconnection comprises merger of one of said generally upright channels with a next adjacent generally upright channel at the conjuncture of said third channel wherein structure is provided defining a slope of a portion of said third channel adjacent said conjuncture, thereby providing for operative serial transfer of the camways past the cam follower.
 14. A writing instrument as recited in claim 13, wherein structure is provided defining a filler slot connection with at least one of said channels.
 15. A writing instrument as recited in claim 7, wherein structure is provided defining a vertical channel extending from said inward turned portion of the first channel to a position above the upward extent of the upper cam element.
 16. A writing instrument as recited in claim 15, wherein in a plurality of said camways is provided, each said camway having a channel interconnection on each side with an adjacent said camway.
 17. A writing instrument as recited in claim 7, wherein structure is provided joining the first and second said channels in ''''V'''' configuration below the lower element, and wherein the bottom portion of the lower cam element is laterally offset with respect to the V configuration, thereby providing for the first said channel to descend past the cam follower on operation beginning with the storage position.
 18. A writing instrument as recited in claim 17, wherein a plurality of camways is provided in lateral juxtaposition, each said camway having a channel interconnection on each side with an adjacent said camway.
 19. A writing instrument as recited in claim 17, wherein structure is provided defining a bellmouth filler slot connection with at least one of said channels.
 20. A writing instrument as recited in claim 7, wherein structure is provided defining the lower portions of the first and second generally upright channels as substantially straight and parallel with the lower ends closed, the lower cam element thereby being in the form of a peninSula.
 21. A writing instrument as recited in claim 20, wherein a plurality of said camways is provided in lateral juxtaposition, each said camway having a channel interconnection on each side to an adjacent said camway.
 22. A writing instrument as recited in claim 6, wherein the cam follower extends radially inwardly and the means on the housing means fixes the cam follower to the housing means, and wherein the camway comprises an exterior cylindrical surface and the means on the plunger means fixes the camway to the plunger means.
 23. A writing instrument as recited in claim 6, wherein the camway comprises an interior cylindrical surface and the means on the housing means fix the camway to the housing means, and wherein the cam follower extends radially outwardly and the means on the plunger means fixes the cam follower to the plunger means.
 24. A writing instrument as recited in claim 6, wherein the cam follower comprises at least one inward protrusion affixed in the inner surface of the upper part of the housing means.
 25. A writing instrument as recited in claim 24, wherein the upper part of the housing means is divided into the shape of a fork, wherein the inward protrusion is affixed to one part of the fork, and wherein a second inward protrusion is provided affixed to a second part of the fork.
 26. A writing instrument as recited in claim 6, wherein the means on the housing means comprises an annular-recess.
 27. A writing instrument as recited in claim 26, wherein the means on the plunger means comprises a flange integral with the plunger means.
 28. A writing instrument as recited in claim 27, wherein a circular shape holder retained in the annular recess in the housing means secures the cam follower in the inner surface of the circular shape holder and wherein the camway comprises an exterior cylindrical surface movable with the plunger means.
 29. A writing instrument as recited in claim 28, wherein the circular shape holder has a resilient arm attached thereto, and wherein the cam follower is affixed to the resilient arm.
 30. A writing instrument as recited in claim 27, wherein the circular shape holder comprises a snapring.
 31. A writing instrument as recited in claim 27, wherein the circular shape holder includes a recess in the inner face receiving the cam follower.
 32. A writing instrument as recited in claim 31, wherein recess is annular and wherein the cam follower comprises a sphere movable in said annular recess.
 33. A writing instrument as recited in claim 30, wherein the recess is radial and wherein the cam follower comprises an elongate member movable in said radial recess.
 34. A writing instrument as recited in claim 26, wherein the housing means is divided transversely at said recess and has internal threads in the divided parts of the recess, wherein a cylindrical member secures the cam follower in the inner face thereof, and wherein the cylindrical member has external threads dimensioned for uniting the threaded divided parts of the housing means.
 35. A writing instrument as recited in claim 6, wherein a circular shape holder engages the flange of the plunger means and wherein the cam follower protrudes outwardly from the circular shape holder.
 36. A writing instrument as recited in claim 35, wherein the circular shape holder is a snapring.
 37. A writing instrument as recited in claim 35, wherein the circular shape holder has a recess therein receiving the cam follower.
 38. A writing instrument as recited in claim 37, wherein the recess is annular, and wherein the cam follower is a sphere movable in said annular recess.
 39. A writing instrument as recited in claim 37, wherein the recess is radial and wherein the cam follower comprises an elongate member movable in said radial recess.
 40. A writing instrument as recited in claim 6, wherein the camway comprises an inward facing integral part of the interior surface of the housing means.
 41. A writing instrument as recited in claim 26, whereiN the camway comprises an inward facing portion of a cylindrical sleeve divided longitudinally into plural parts and wherein the plural parts are retained in the annular recess in the housing means and means for requiring return of the lead holding means to said writing position after feeding lead through the lead holding means. 